1. Field of the Invention
This invention relates to a method for interconnecting adjacent electrical storage batteries into a single battery system using a fusible alloy.
2. Description of the Prior Art
Heretofore, in connecting adjacent batteries in a battery system a method of clamp-connecting a conductor such as a copper plate or a copper wire to the terminals of the batteries by the use of bolts and nuts has been used most frequently. However, such connections suffer from the shortcomings of acid mist or alkali mist generated during the charging of the batteries being deposited on the upper surfaces of the batteries, the mist tending to filtrate into the gap between the terminal and the connecting conductor thereby corroding the contacting surfaces of the terminal and the conductor. Furthermore, since the terminal and the connecting conductor are simply clamped together by means of the bolts and nuts, the contacting surfaces of the terminal and the conductor tend to deteriorate, thereby increasing the contact resistance and the voltage drop thereacross. Furthermore, such increase in the contact resistance and the voltage drop tends to reduce the discharge capacities of the batteries and/or generates heat at the contact parts, thus giving rise to further degradation in the operation of the batteries.
To eliminate the above described drawbacks of the clamp-type connecting method, a soldering alloy (Pb-Sb alloy) procedure has been used for connecting the terminals of the batteries and the conductors. However, this procedure utilizes a soldering alloy having a melting temperature higher than 220.degree. C. Recently, synthetic resin covers have been widely used for batteries, and there has been a tendency for the heat from the soldering alloy to melt a part of the synthetic resin cover. This in turn tends to deteriorate the air seal where the terminal penetrates the cover, allowing the acid mist or alkali mist created during the charging of the battery to escape through the gap created between the terminal and the cover and condense on the upper surface of the battery, thus creating a leakage current path between the anode and cathode of the battery.
A procedure has also been proposed wherein the heat generated at the time of making the soldering connection is prevented from being conducted to the cover of the battery. However, this procedure is also unsatisfactory because it requires a special jig and the connecting operation is rather complicated.